论文标题
$ z \ simeq6 $带有深jwst/nircam成像的lyα星系的Hα印象
An Hα Impression of Lyα Galaxies at $z\simeq6$ with Deep JWST/NIRCam Imaging
论文作者
论文摘要
我们使用$ JWST $/NIRCAM成像数据介绍了七个光谱镜确认（LY $α$发射）星系的研究。这些星系在一系列Nircam Broad和中带中观察到了这些星系，具有广泛的LY $α$亮度。我们使用$ JWST $/NIRCAM和Archival $ HST $/WFC3红外光度法的组合来限制RETART-FRAME UV/OPTICAL CONTINUA，并测量星系的H $α$线排放。我们进一步估计它们的逃逸分数（$ f _ {\ rm ESC}^{\ rmlyα} $）和电离光子的生产效率（$ξ_ {\ rm ion ion} $）。在样本中，6/7星系的$α$逃脱分数为$ {\ lyssim} 10 \％$，这可能是大多数$ z \ simeq6 $的大多数星形星系的状态。一个带有极蓝色紫外线的UV-PART ly $α$ alaxy拥有$ f _ {\ rm esc}^{\ rmlyα} $的大价值，到达$ {\ simeq} 50 \％$。这些星系在日志$ _ {10} $ $ $ $ $ $ $ _ {\ rm ion，0} $（hz erg $^{ - 1} $）$ \ sim25.0-26.5 $上传播了$ξ_ {\ rm ion} $的广泛范围。我们发现，带有蓝色紫外线连续斜率的紫外线效果可能具有较高的$α$光子的逃生部分。我们还发现，具有较高LY $α$线发射的星系倾向于更有效地产生电离光子。样品中最log的$α$ - 露骨星系具有很高的$ξ_ {\ rm ion，0} $ log $ _ {10} $ $ $ $ $ $ $ $ $ $ $ $之一，\ rm ion，0} $（hz erg $^{ - 1}} $> 26 $ 26 $。我们的结果支持$α$星系可能是宇宙电离的重要贡献者。蓝色和明亮的LY $α$星系是$ JWST $随访光谱观测的绝佳目标。
We present a study of seven spectroscopically confirmed (Ly$α$ emitting) galaxies at redshift $z\simeq6$ using the $JWST$/NIRCam imaging data. These galaxies, with a wide range of Ly$α$ luminosities, were recently observed in a series of NIRCam broad- and medium-bands. We constrain the rest-frame UV/optical continua and measure the H$α$ line emission of the galaxies using the combination of the $JWST$/NIRCam and archival $HST$/WFC3 infrared photometry. We further estimate their escape fractions of Ly$α$ photons ($f_{\rm esc}^{\rm Lyα}$) and the production efficiency of ionizing photons ($ξ_{\rm ion}$). Among the sample, 6/7 galaxies have Ly$α$ escape fractions of ${\lesssim}10\%$, which might be the status for most of star-forming galaxies at $z\simeq6$. One UV-faint Ly$α$ galaxy with an extremely blue UV slope owns a large value of $f_{\rm esc}^{\rm Lyα}$ reaching ${\simeq}50\%$. These galaxies spread a broad range of $ξ_{\rm ion}$ over log$_{10}$ $ξ_{\rm ion, 0}$ (Hz erg$^{-1}$) $\sim25.0-26.5$. We find that UV-fainter galaxies with bluer UV continuum slopes likely have higher escape fractions of Ly$α$ photons. We also find that galaxies with higher Ly$α$ line emission tend to produce ionizing photons more efficiently. The most Ly$α$-luminous galaxy in the sample has a very high $ξ_{\rm ion, 0}$ of log$_{10}$ $ξ_{\rm ion, 0}$ (Hz erg$^{-1}$) $>26$. Our results support that Ly$α$ galaxies may have served as an important contributor to the cosmic reionization. Blue and bright Ly$α$ galaxies are excellent targets for $JWST$ follow-up spectroscopic observations.
